Enhanced electrochemical performance of cobalt oxide nanocube intercalated reduced graphene oxide for supercapacitor application

Abstract

We investigated different molar concentrations of cobalt precursor intercalated reduced graphene oxide (rGO) as possible electrode materials for supercapacitors. Cobalt oxide (Co₃O₄) nanocubes intercalated reduced graphene oxides (rGO) were synthesized via a facile hydrothermal method. It has been found that the Co₃O₄ particles with a cubical shape are decorated on rGO matrix with an average size of ∼45 nm. The structural crystallinity of rGO–Co₃O₄ composites was examined by X-ray diffraction (XRD). Raman spectroscopy confirmed the successful reduction of GO to rGO and effective interaction between Co₃O₄ and the rGO matrix. The electrochemical performances of rGO–Co₃O₄ electrodes were examined using cyclic voltammetry and charge–discharge techniques. The maximum specific capacitance (278 F g⁻¹) is observed at current density of 200 mA g⁻¹ in the C2 electrode resulting from effective ion transfer and less particle aggregation of Co₃O₄ on the rGO matrix than in the other electrodes. C2 exhibits good rate capability and excellent long-term cyclic stability of 91.6% for 2000 cycles. The enhanced electrochemical performance may result from uniform intercalation of cobalt oxide over the rGO. These results suggest that the Co₃O₄ intercalated rGO matrix could play a role in improved energy storage capability.